Phytoplanktonic primary production modulated by coastal geomorphology in a highly dynamic environment of central Chile

Abstract

Resumen.-La circulación asociada a surgencias costeras tiene un efecto regional sobre la comunidad fitoplanctónica (i.e. aumento de las tasas fotosintéticas, incremento en biomasa), pero su influencia a escalas espaciales locales es menos clara. A una escala local (cientos de metros) y bajo condiciones de surgencia, zonas de retención con altos niveles de producción primaria (PP) tienden a ocurrir en el lado protegido de pequeñas penínsulas inducidas por la orientación, geometría, tamaño y geomorfología general de este tipo de formaciones costeras. Nosotros cuantificamos producción primaria neta (NPP), bruta (GPP), respiración comunitaria (CR) y biomasa (Chl-a) de ensambles naturales de fitoplancton en ambientes costeros de Chile central. El principal objetivo fue determinar un patrón a corto plazo en PP y CR en ambos lados de dos pequeñas penínsulas en Chile central, donde son esperables diferencias mensurables en varias variables ambientales. Nuestra hipótesis de trabajo es que estas diferencias no ocurren bajo condiciones de relajación o de no-surgencia. Los resultados indican que NPP, GPP y CR difieren a una escala local y, contrariamente a lo reportado previamente, encontramos que el debilitamiento de los vientos favorables a las surgencias pueden generar un patrón opuesto a lo observado durante un periodo activo de surgencia, donde el sitio expuesto retiene altas concentraciones de biomasa y exhibe elevados niveles de PP comparados con el sitio protegido. Nuestros resultados destacan la importancia de la variabilidad a corto plazo de PP y CR y su acople con la distribución y abundancia del fitoplancton y su rápida respuesta a una escala espacial local.Palabras clave: Oceanografía costera, surgencia, biomasa fitoplanctónica, flujo de carbono, morfología costera Abstract.-Coastal upwelling circulation has a regional fertilizing effect upon phytoplanktonic communities (i.e. enhancement of photosynthetic rates, increased biomass), but its influence at smaller spatial and temporal scales is less clear. At local scale (100's m) and under upwelling-favorable conditions, retention zones with higher primary production (PP) levels tend to occur at the lee or protected side of small headlands induced by the orientation, geometry, size and general geomorphology of these coastal formations. Here we quantified net and gross primary production (NPP and GPP), community respiration (CR) and biomass (Chl-a) of natural phytoplankton assemblages in coastal environments of central Chile. The main goal was to determine short-term patterns in PP and CR around two small peninsulas in central Chile where measurable differences in several environmental variables can be expected, and we hypothesize that differences will no longer occur under non-upwelling/relaxation conditions. Results indicate that NPP GPP and CR differ at local scale, and contrary to previous findings we found that weakening of upwelling-favorable winds can generate an opposite pattern to that observed under active upwelling periods, whereas the exposed site retai...

Long term environmental variability modulates the epigenetics of maternal traits of kelp crabs in the coast of Chile

“…From a perspective of maternal investment on offspring, more specific studies are required to unravel the close mechanisms that link DNA methylation to lipid metabolism in the early ontogeny of marine invertebrates. Nevertheless, this trend of increasing methylation with latitude also followed the general pattern of productivity along the coast evidenced in our climatologies, which is mostly driven by the influence of wind-driven coastal upwelling events near Punta de Tralca (PT) (Palma et al 41 ) and Los Cuervos (CU) beach in San Vicente Bay 42 and the influence of nutrients loading from Valdivia River estuary near Los Molinos (LM) 43 and the Gulf of Ancud (AN) 44 . Although we did not measure the productivity of kelp forests as food supply for T. dentatus in upwelling www.nature.com/scientificreports/ sites, different studies have shown that macroalgae grow faster and attain larger biomass in association with the upwelling sites off Central Chile 28,29 .…”

Territorial User Rights for Fisheries as Ancillary Instruments for Marine Coastal Conservation in Chile

“…In Chile primary production of plankton on opposite sides of small peninsulas can differ significantly (Henríquez et al 2007). However, these patterns can be extremely variable over time (Palma et al 2009). As a way to minimize this possible effect, we sampled along both the exposed and protected sides of small peninsulas in open access areas.…”

Distribution patterns, larval growth and hatch dates of early stages of the mote sculpin Normanichthys crockeri (Scorpaeniformes, Normanichthyidae) in the upwelling ecosystem off central Chile

“…Although more recently an opposite pattern has been described whereas the weakening of upwellingfavorable winds favors the retention, along exposed sides of small headlands, of phytoplankton and associated primary production (Palma et al 2009). Since larvae of N. crockeri are vertically distributed in surface waters and feed on microplankton (mostly copepod eggs, copepods and tintinids, Balbontín et al 1997), protected sites around headlands along central Chile are optimal locations where the feeding success and larval growth of N. crockeri can occur.…”